Various suggestions and/or devices have heretofore been presented for exciting and detecting a surface acoustic wave (SAW) on a piezoelectric media. In addition, use has heretofore been made of such devices in convolvers.
Heretofore, a device known as the interdigital transducer (IDT) has been the most efficient device found for exciting and detecting such waves, and a configuration utilizing a two-layer transducer on lithium niobate has been heretofore used for doubling the frequency range for LiNbO.sub.3 SAW devices. In addition, while various other grating array transducer schemes have been suggested and/or demonstrated on single crystal structures, such schemes have not been found to be completely acceptable, due, at least in part, to unacceptable degration in such transducers.
The conventional interdigital transducer, however, has likewise not been found to be completely acceptable, in that such transducers require metal widths and spacings of one quarter of the wavelength of the SAW device, and presents yield disadvantages, at least in some instances, including use in convolvers.